If you want to play docker on Ubuntu 14.04, please pay attention to the installation instruction: it is “apt-get install docker.io“, not “apt-get install docker“. You can find the difference between them by following command:
# apt-cache search docker
......
docker - System tray for KDE3/GNOME2 docklet applications
......
docker.io - Linux container runtime
......
OK! Since you have set up docker successfully, you can check its process now:
# ps -ef | grep docker
root 4715 1 0 13:22 ? 00:00:00 /usr/bin/docker -d
root 4857 4691 0 13:50 pts/0 00:00:00 grep --color=auto docker
# pstree -ps 4715
init(1)───docker(4715)─┬─{docker}(4717)
├─{docker}(4722)
├─{docker}(4723)
├─{docker}(4724)
├─{docker}(4734)
├─{docker}(4754)
├─{docker}(4762)
├─{docker}(4769)
└─{docker}(4793)
You can use “service start docker” and “service stop docker” to start and stop docker daemon.
If your host runs behind proxy, you may meet problems when pulling image:
# docker run hell-world
Unable to find image 'hell-world:latest' locally
Pulling repository hell-world
FATA[0005] Get https://index.docker.io/v1/repositories/library/hell-world/images: x509: certificate is valid for FG3K6C3A15800021, not index.docker.io
The solution is add proxy configurations in /etc/default/docker:
......
# If you need Docker to use an HTTP proxy, it can also be specified here.
export http_proxy="http://web-proxy.corp.xxxxxx.com:8080/"
export https_proxy="https://web-proxy.corp.xxxxxx.com:8080/"
......
Then you can download images successfully:
# docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from hello-world
d59cd4c39e50: Pull complete
f1d956dc5945: Pull complete
Digest: sha256:4f32210e234b4ad5cac92efacc0a3d602b02476c754f13d517e1ada048e5a8ba
Status: Downloaded newer image for hello-world:latest
Hello from Docker.
This message shows that your installation appears to be working correctly.
......
Now that all the preparations are ready, please enjoy playing docker!